Bond Strength between Different Zirconia-Based Ceramics and Resin Cement before and after Aging
, Nathália de Carvalho Ramos 1,2, Guilherme da Rocha Scalzer Lopes 1, João Paulo Mendes Tribst 3,* and Marco Antonio Bottino 1
Round 1
Reviewer 1 Report
The study is very interesting, well conducted and of high clinical interest.
INTRODUCTION
Line 56 – the reference is missing.
Line 67 – replace “ceramic” for “material”.
DISCUSSION
Line 202 – the reference is missing.
The authors refer in the conclusions: “…Based on all the information provided by this study and even with its limitations,…” but they do not discuss the limitations in the discussion. They should do it.
Author Response
The study is very interesting, well conducted and of high clinical interest.
R: Dear reviewer, thank you very much for your time and effort evaluating this study.
INTRODUCTION
Line 56 – the reference is missing.
R: The reference has been inserted.
Line 67 – replace “ ceramic” for “ material” .
R: It was done.
DISCUSSION
Line 202 – the reference is missing.
R: The reference has been inserted.
The authors refer in the conclusions: “… Based on all the information provided by this study and even with its limitations,…” but they do not discuss the limitations in the discussion. They should do it.
R: The limitations of this study was added in discussion section.
Reviewer 2 Report
The manuscript submitted for evaluation deals with the bond strength between zirconia ceramics and resin cement. Article is well prepared and after some corrections can be published in Coatings journal.
Major comments:
1. English should be corrected.
2. Title should be corrected. “Long-term” phrase suggests long-term research results, and yet the authors performed thermal fatigue (thermocycles). Moreover, "high translucency zirconia" can also be misleading. After all, the authors presented the results for 4 varieties of zirconia with different translucency, including one defined as "high translucency".
3. According to above, the aim of the work should also be corrected.
4. In the introduction, a description of the problem marked in the title: adhesion between ceramics and cement, is lost.
5. Lines 67-70: I have the impression that the authors do not fully understand what changes occur in ceramics during sintering. In fact, the parameters of the sintering process (apart from the chemical composition and grain size) influence the structure and properties of ceramics.
6. Lines 72-73: “It is known that the structural changes to increase translucency affected the mechanical behavior of the zirconia” – please specify whether they increase or decrease the mechanical properties.
7. Table 2: the second and last columns show the percentages which are in each case 100%. What are these values about? Is it worth posting them if it is 100% in each case?
8. Table 2 (cont.): penultimate column - is it cooling rate or end temperature ?
9. Table 2 (cont.): fast mode, 80 min - please explain in the table, does 80 min replace 120 min of sintering or is it the total operation time in the furnace?
10. Line 112: how was the distance of 1 cm kept constant?
11. Line 127: The unit of force is newton [N], not Kgf. Please, enter a valid value.
12. Please justify the application of the shear test to the real operating conditions of the ceramic restorations.
13. 2.4. Failure analysis: it was mentioned, that stereomicroscope was used. However, in result section Authors presented SEM images. Please, correct methodology.
14. Discussion section should be improved. Paragraphs 2nd and 4th to 6th are in fact descriptions of each kind of ceramics used and add nothing to the discussion.
15. This manuscript, unfortunately like many others, seems to treat the materials as a "black box". The authors do not analyze the factors that improve or reduce adhesion, but only deal with the final effect. Therefore, there is a serious limitation here - the results and final conclusions relate only to this particular set of materials and cannot be generalized.
16. The authors use a simplification regarding the translucency of ceramics. In my opinion, the term "translucency level" cannot be used freely, because this level depends on many factors. Translucency in materials from different manufacturers may differ significantly.
Minor comments:
1. No explanation of material designations in table 1
2. Line 96: “sample calculation” – did the Authors mean “sample size calculations” using power analysis?
3. Line 126: “steel wire loop” instead of “steel wire”
4. Last sentence of subchapter 2.5 should be rewritten
5. Remove title from the chart (Fig. 3) and complete explanations of the boxes. Moreover, the order of presentation of results does not agree with the order of materials in tables 1 and 2 and in fig. 1
6. Tab. 3: no clear separation of the table into aged and unaged materials
7. Line 196: Table 4 instead of Table 3
Author Response
The manuscript submitted for evaluation deals with the bond strength between zirconia ceramics and resin cement. Article is well prepared and after some corrections can be published in Coatings journal.
A: Dear reviewer, thank you very much for your time and effort in evaluating this study. We appreciate your vauable comments.
Major comments:
- English should be corrected.
R: English language revision has been performed.
- Title should be corrected. “Long-term” phrase suggests longterm research results, and yet the authors performed thermal fatigue (thermocycles). Moreover, "high translucency zirconia" can also be misleading. After all, the authors presented the results for varieties of zirconia with different translucency, including one defined as "high translucency".
R: Dear reviewer, thank you for your suggestion. To avoid misunderstandings between different brands, the translucency of the materials has been replaced by its composition (yttria content). Therefore the title was rewritten. However, “Long term” is often used to refer to a future behavior, which is the case in this work. A thermal aging was performed to predict the behavior of these adhesive interfaces after a simulated period of clinical usage in a humid environment and with temperature variations (such as the oral cavity).
- According to above, the aim of the work should also be corrected.
R: We hope that now the objective and title are better defined.
- In the introduction, a description of the problem marked in the title: adhesion between ceramics and cement, is lost.
R: Third and fourth paragraphs were modified to highlight the problem.
- Lines 67-70: I have the impression that the authors do not fully understand what changes occur in ceramics during sintering. In fact, the parameters of the sintering process (apart from the chemical composition and grain size) influence the structure and properties of ceramics.
R: New information regarding the sintering aspects were included.
- Lines 72-73: “ It is known that the structural changes to increase translucency affected the mechanical behavior of the zirconia” – please specify whether they increase or decrease the mechanical properties.
R: This phrase was completely changed (lines 72-74).
- Table 2: the second and last columns show the percentages which are in each case 100%. What are these values about? Is it worth posting them if it is 100% in each case?
R: The values refers to the opening and closing of the ceramic oven. The 100% indicates that the sample lifting platform is at its maximum, that is, the oven is fully closed. However, these values were removed from the table as they do not provide any relevant information to readers.
- Table 2 (cont.): penultimate column - is it cooling rate or end temperature ?
R: The end temperature. A legend was created to better clarification.
- Table 2 (cont.): fast mode, 80 min - please explain in the table, does 80 min replace 120 min of sintering or is it the total operation time in the furnace?
R: The speed sintering protocol is closed by the manufacturer, there is no information regarding the steps of the protocol. We only know that are 80 min total time (including the heating and cooling time) instead of around 12 hours (total time to conventional sintering protocol). Line 111-113 were included regarding it.
- Line 112: how was the distance of 1 cm kept constant?
R: We used a resin jig to standardize this distance for all specimens’ preparations. It was the handle method to reproduce this parameter fixing the specimen and the sandblasting tip.
- Line 127: The unit of force is newton [N], not Kgf. Please, enter a valid value.
R: Our loading cell is described by the manufacturer as 25kgf, so the value was modified to 250N.
- Please justify the application of the shear test to the real operating conditions of the ceramic restorations.
R: The requested information can be found in the lines 263-281.
- 2.4. Failure analysis: it was mentioned, that stereomicroscope was used. However, in result section Authors presented SEM images. Please, correct methodology.
R: It was corrected.
- Discussion section should be improved. Paragraphs 2 and 4 to 6 are in fact descriptions of each kind of ceramics used and add nothing to the discussion.
R: Those paragraphs includes information regarding the ceramic used in this study. Some points were updated in discussion section and hopefully are better described now.
- This manuscript, unfortunately like many others, seems to treat the materials as a "black box". The authors do not analyze the factors that improve or reduce adhesion, but only deal with the final effect. Therefore, there is a serious limitation here - the results and final conclusions relate only to this particular set of materials and cannot be generalized.
R: We changed the approach of material’s factor, instead of the level of translucency, we now named them by their composition (yttria content). Thus, we believe that the results can be generalized to similar materials.
- The authors use a simplification regarding the translucency of ceramics. In my opinion, the term "translucency level" cannot be used freely, because this level depends on many factors.
Translucency in materials from different manufacturers may differ significantly.
R: As mentioned before, we avoid to refer to “translucency level”.
Minor comments:
- No explanation of material designations in table 1
R: The zirconia’s description were added in the text before the Table 1 mention.
- Line 96: “ sample calculation” – did the Authors mean “ sample size calculations” using power analysis?
R: This information was included.
3.Line 126: “ steel wire loop” instead of “ steel wire”
R: OK.
- Last sentence of subchapter 2.5 should be rewritten
R: The phrase was rewritten: “The Weibull modulus determine the structural homogeneity of the adhesive interfaces (reliability), and with this analysis is also calculated the characteristic bonding strength, which is the strength where 63.2% of the adhesive interfaces will fail”.
- Remove title from the chart (Fig. 3) and complete explanations of the boxes. Moreover, the order of presentation of results does not agree with the order of materials in tables 1 and 2 and in fig. 1
R: Figure 3 was modified.
- Tab. 3: no clear separation of the table into aged and unaged materials
R: It was corrected.
- Line 196: Table 4 instead of Table 3
R: Corrected.
Thank you once again for the possibility of improving our manuscript and publishing it in Metals.
Sincerely,
The authors.
Reviewer 3 Report
Dear Author,
in attach you will find some remarks
Best regards
Comments for author File: 
Comments.pdf
Author Response
Dear Author,
in attach you will find some remarks
Best regards
Dear reviewer, thank you very much for your time and effort in evaluating this study. We appreciate your vauable comments. All the required modifications have been done in the attached manuscript.
Best regards
Round 2
Reviewer 2 Report
Dear Authors,
I still have objections about the phrase “Long-term” in the title. I would like to suggest that you specify that it is about thermal aging, especially since it was so defined for the purpose of the work. It should be consistent.
Caption of Fig. 3 contains abbreviations referring to the sintering method (C and S), but they were not used in the diagram. Moreover, the term “Speed” should rather be replaced by “Rapid”
I have no objection to the other amendments.
Author Response
Dear Authors,
I still have objections about the phrase “Long-term” in the title. I would like to suggest that you specify that it is about thermal aging, especially since it was so defined for the purpose of the work. It should be consistent.
Dear reviewer, to avoid misunderstandings we have modified the title as suggested.
Caption of Fig. 3 contains abbreviations referring to the sintering method (C and S), but they were not used in the diagram. Moreover, the term “Speed” should rather be replaced by “Rapid”
Figure 3 legend has been corrected as suggested.
I have no objection to the other amendments.
Thank you. Your suggestions were very useful.
Reviewer 3 Report
Dear Author,
I appreciate that you found my suggestion useful
Best regards
Author Response
Dear Author,
I appreciate that you found my suggestion useful
Best regards
Dear reviewer, thank you very much.
